The goal of this proposal is to develop and test a novel high throughput assay capable of screening hundreds of thousands of compounds for effects on replicative lifespan in the yeast Saccharomyces cerevisiae. Key aspects of aging are conserved between yeast and humans, including signaling, regulatory, and effector pathways. Yeast has been a valuable model system for the discovery and elucidation of conserved aging genes such as SIR2 and their modes of regulation, but only the surface of the field has been scratched. The screening of chemical libraries with this assay should result in the identification of compounds that affect the activities of known and as yet undiscovered cellular targets with roles in aging and lifespan. The "death of daughters" (DEAD) replicative lifespan assay provides cell-based phenotypic screen that will allow us to address an entirely new order of questions about the molecular mechanism and control of aging and lifespan. This high throughput assay will allow us to investigate the genomics of lifespan, screen chemical libraries for compounds that affect lifespan, and study the genetics of lifespan among natural populations. The specific aims of this proposal are directed at developing optimized genetic platforms and automated high throughput assay formats with simple readouts for replicative lifespan. The long term goal of this project is to saturate the function yeast genome (the proteome) with compounds that affect lifespan, many of which should find applications to both basic and applied studies. Since approximately one out of five yeast genes has a human homolog, we believe it likely that some of these targets, and their roles in aging or age-related diseases, will be conserved in humans. Thus, yeast remains fertile ground for gene discovery, for the elucidation of conserved aging mechanisms, and for studies of functional senescence. [unreadable] [unreadable]